<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes" />
    <title>ShellCheck: SC1137 – Missing second `(` to start arithmetic for ((;;)) loop</title>
    <link rel="stylesheet" href="css/bootstrap.min.css" />
  </head>
  <body style="margin-left: auto; margin-right: auto; max-width: 800px">
    <h1>SC1137 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC1137">See this page on GitHub</a>
    <p style="display: none"><a href="index.html">Sitemap</a></p>
    <hr />
    <h2 id="missing-second--to-start-arithmetic-for--loop">Missing second
<code>(</code> to start arithmetic for ((;;)) loop</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC1137.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="cf">for</span> <span class="kw">(</span><span class="va">i</span><span class="op">=</span>0<span class="kw">;</span> <span class="ex">i</span><span class="op">&lt;</span>10<span class="kw">;</span> <span class="ex">i++</span><span class="kw">)</span><span class="er">)</span></span>
<span id="cb1-2"><a href="SC1137.html#cb1-2" aria-hidden="true" tabindex="-1"></a><span class="cf">do</span></span>
<span id="cb1-3"><a href="SC1137.html#cb1-3" aria-hidden="true" tabindex="-1"></a>  <span class="bu">echo</span> <span class="va">$i</span></span>
<span id="cb1-4"><a href="SC1137.html#cb1-4" aria-hidden="true" tabindex="-1"></a><span class="cf">done</span></span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC1137.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="cf">for</span> <span class="kw">((</span><span class="va">i</span><span class="op">=</span><span class="dv">0</span><span class="kw">;</span> <span class="va">i</span><span class="op">&lt;</span><span class="dv">10</span><span class="kw">;</span> <span class="va">i</span><span class="op">++</span><span class="kw">))</span></span>
<span id="cb2-2"><a href="SC1137.html#cb2-2" aria-hidden="true" tabindex="-1"></a><span class="cf">do</span></span>
<span id="cb2-3"><a href="SC1137.html#cb2-3" aria-hidden="true" tabindex="-1"></a>  <span class="bu">echo</span> <span class="va">$i</span></span>
<span id="cb2-4"><a href="SC1137.html#cb2-4" aria-hidden="true" tabindex="-1"></a><span class="cf">done</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>ShellCheck found an arithmetic <code>for ((;;))</code> expression
where either the <code>((</code> or the <code>))</code> did not come as
a pair. Make sure to use <code>(( ))</code> and not
<code>( )</code>.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>None.</p>
<h3 id="related-resources">Related resources:</h3>
<ul>
<li>Help by adding links to BashFAQ, StackOverflow, man pages, POSIX,
etc!</li>
</ul>
    <hr />
    <p style='font-size: 80%'><a href="../index.html">ShellCheck</a> is a static analysis tool for shell scripts. This page is part of its documentation.</p>
  </body>
</html>


